Hi all,
Looking for a bit of advice on troubleshooting my 5 gen combo spirit run on UJSSM. I've googled, searched the forum and used the AD Search to no avail, so apologies if this has been asked and answered somewhere else.
Problem: five generations of UJSSM combined low wines for a spirit run, end product tastes flavourless and bad. Acrid, iodine-y after taste and a hint of heads prickle on the tongue across all cuts and down into tails; however, the stripping runs smelled great (butterscotch and corn). Stole a bit of the hearts of Gen 5 and "force aged" it to get an idea of flavour profile and it was pretty good (and I'm not a bourbon drinker).
Background Info: 23L batch generations, raw sugar used instead of white, feed grade cracked corn (probably only 1-2 cracks per kernel), 7L backset used for every generation aside from first, ~3300ml low wines collected from each stripping run (200ml foreshots discarded each run) taken down to 25%, no issues with ferments - all finished dry within 7-10 days (on a beer brewers heat pad set to 25 degrees but would've dropped overnight for some gens). Third Gen only got to 1.010 but I just ran it anyway. Lowan's bakers yeast used.
Spirit run: 22L boiler charge (once low wines diluted to ~40%), another 200ml discarded for fores (just in case), dropped energy input to under half once close to product off-take and ran at a thin, broken stream for the whole run. Fores came off at 87%, hearts (when tasting off the still) at 80% and tails at roughly 45%. After leaving open to off-gas for ~15hrs, went to sample cuts in order to blend and everything tasted bitter, astringent, no flavour and a bit heads prickly.
Still: 50L keg CCVM run in pot still mode, 1 x 2000W element hooked up to a 5 Star voltage regulator, 2 inch copper column at 1200mm, 2inch shotgun condenser at 500MM.
Working theory: I've either run it too quick and smeared heads into everything, or got some passive reflux from the column and the ABV is too high to carry over any flavour congeners with the ethanol. Looking at an ethanol liquid/vapour chart, 40% shouldn't be hitting 87% without some sort of reflux.
Any help much appreciated in figuring out where I've gone wrong and whether it is salvagable or not. I'm trying my luck and running the whole thing again with the column insulated and much slower off-take.
Apologies if I missed any crucial info.
Thanks all